linux-kernel - Re: [PATCH] i2c: riic: Simplify reset handling

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Date:   Thu, 17 Feb 2022 20:51:22 +0100
From:   Wolfram Sang <wsa@...nel.org>
To:     Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Chris Brandt <chris.brandt@...esas.com>,
        Philipp Zabel <p.zabel@...gutronix.de>
Cc:     Geert Uytterhoeven <geert+renesas@...der.be>,
        linux-renesas-soc@...r.kernel.org, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Prabhakar <prabhakar.csengg@...il.com>,
        Biju Das <biju.das.jz@...renesas.com>
Subject: Re: [PATCH] i2c: riic: Simplify reset handling

On Wed, Feb 09, 2022 at 11:22:32PM +0000, Lad Prabhakar wrote:
> Read reset phandle as optional instead of exclusive so that all the DT's
> passing the reset phandle can be used to assert/deassert the reset line.
> With this change we don't have to differentiate the RZ/G2L SoC.
> 
> With the above changes we no longer need the "renesas,riic-r9a07g044"
> compatible string, so drop it from riic_i2c_dt_ids[]. No changes are
> required to the r9a07g044.dtsi as we already have "renesas,riic-rz" as a
> fallback compatible string.
> 
> While at it, check the return code of reset_control_deassert() as it might
> fail and also add a devres action to assert the reset line.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>

Looks good to me. Chris, Philipp what do you think?

> ---
>  drivers/i2c/busses/i2c-riic.c | 34 +++++++++++++++++-----------------
>  1 file changed, 17 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
> index 8dfd27dc6149..cded77e06670 100644
> --- a/drivers/i2c/busses/i2c-riic.c
> +++ b/drivers/i2c/busses/i2c-riic.c
> @@ -88,11 +88,6 @@
>  
>  #define RIIC_INIT_MSG	-1
>  
> -enum riic_type {
> -	RIIC_RZ_A,
> -	RIIC_RZ_G2L,
> -};
> -
>  struct riic_dev {
>  	void __iomem *base;
>  	u8 *buf;
> @@ -396,6 +391,11 @@ static struct riic_irq_desc riic_irqs[] = {
>  	{ .res_num = 5, .isr = riic_tend_isr, .name = "riic-nack" },
>  };
>  
> +static void riic_reset_control_assert(void *data)
> +{
> +	reset_control_assert(data);
> +}
> +
>  static int riic_i2c_probe(struct platform_device *pdev)
>  {
>  	struct riic_dev *riic;
> @@ -404,7 +404,6 @@ static int riic_i2c_probe(struct platform_device *pdev)
>  	struct i2c_timings i2c_t;
>  	struct reset_control *rstc;
>  	int i, ret;
> -	enum riic_type type;
>  
>  	riic = devm_kzalloc(&pdev->dev, sizeof(*riic), GFP_KERNEL);
>  	if (!riic)
> @@ -421,16 +420,18 @@ static int riic_i2c_probe(struct platform_device *pdev)
>  		return PTR_ERR(riic->clk);
>  	}
>  
> -	type = (enum riic_type)of_device_get_match_data(&pdev->dev);
> -	if (type == RIIC_RZ_G2L) {
> -		rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
> -		if (IS_ERR(rstc)) {
> -			dev_err(&pdev->dev, "Error: missing reset ctrl\n");
> -			return PTR_ERR(rstc);
> -		}
> +	rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
> +	if (IS_ERR(rstc))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(rstc),
> +				     "Error: missing reset ctrl\n");
>  
> -		reset_control_deassert(rstc);
> -	}
> +	ret = reset_control_deassert(rstc);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_add_action_or_reset(&pdev->dev, riic_reset_control_assert, rstc);
> +	if (ret)
> +		return ret;
>  
>  	for (i = 0; i < ARRAY_SIZE(riic_irqs); i++) {
>  		ret = platform_get_irq(pdev, riic_irqs[i].res_num);
> @@ -492,8 +493,7 @@ static int riic_i2c_remove(struct platform_device *pdev)
>  }
>  
>  static const struct of_device_id riic_i2c_dt_ids[] = {
> -	{ .compatible = "renesas,riic-r9a07g044", .data = (void *)RIIC_RZ_G2L },
> -	{ .compatible = "renesas,riic-rz", .data = (void *)RIIC_RZ_A },
> +	{ .compatible = "renesas,riic-rz", },
>  	{ /* Sentinel */ },
>  };
>  
> -- 
> 2.17.1
> 

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